Combined Transcranial Sonography of the
Substantia
Nigra and
18
F‐Fluorodeoxyglucose
Positron
Emi
Tong Wu, Ziwei Zhou, Wenjie Gong, Jinju Sun, Weicheng Zhou, Xin Li, Jingqin Fang, Xiao Chen Abstract
Background
Accurate differentiation between Parkinson's disease (PD) and atypical parkinsonian syndromes (APS) remains challenging where dual‐tracer ( 11 C‐2β‐carbomethoxy‐3β‐(4‐fluorophenyl) tropane [[ 11 C]CFT] and 18 F‐fluorodeoxyglucose [[ 18 F]FDG]) positron emission tomography/computed tomography (PET/CT) access is limited.
Objective
The aim was to investigate whether transcranial sonography (TCS) of the substantia nigra (SN) can replace [ 11 C]CFT PET when combined with [ 18 F]FDG PET for diagnosing early PD and differentiating PD from APS.
Methods
Totally 160 patients with suspected PD or APS underwent clinical assessment, SN‐TCS, and PET/CT. PET/CT images were evaluated by visual assessment based on predetermined disease‐specific patterns. Diagnoses of TCS‐SN were performed according to predefined criteria. Diagnostic performance was evaluated using 2 binary comparisons: PD versus non‐PD and APS versus non‐APS.
Results
After a median follow‐up period of 23 months, the final clinical diagnoses were PD (n = 72), APS (n = 50), and parkinsonian syndromes other than PD or APS (n = 33). For diagnosis of PD, combined SN‐TCS with [ 18 F]FDG PET/CT strategy exhibited comparable specificity to dual‐tracer PET/CT (90.4% vs. 95.2%, P = 0.344) but significantly lower sensitivity (34.7% vs. 84.7%, P < 0.001). Compared to TCS alone, the combined approach yielded similar sensitivity (34.7% vs. 36.1%, P = 1.000) and higher specificity (90.4% vs. 72.3%, P < 0.001). For APS diagnosis, this combined approach achieved comparable sensitivity (76.0% vs. 86.0%, P = 0.180), specificity (86.7% vs. 86.7%, P = 1.000), accuracy (83.2% vs. 86.5%, P = 0.302), and the area under the curve (0.81 vs. 0.86, P = 0.115) relative to dual‐tracer PET/CT.
Conclusion
The combination of SN‐TCS and [ 18 F]FDG PET/CT may serve as an effective triage tool for PD with high specificity. For APS, this combined strategy may provide a feasible diagnostic option in settings with limited access to dual‐tracer PET/CT.